ISMNT News #47. For many weeks we had a very controversial discussion on the dose of vitamin C needed for "healthy" life. At the end, no agreement could be reached.

The study by Podmore et al. clearly demonstrates that in healthy humans 500 mg vitamin C per day for 6 weeks can have antioxidant but also pro-oxidant effects. The levels of oxidative damage of peripheral blood lymphocytes in terms of modified DNA bases was assessed. The level of 8-oxoguanine was found to decrease on supplementation whereas the level of 8-oxoadenine increased. The authors conclude that the discovery of an increase in a potentially mutagenic lesion should be of some concern. They suggest that at doses of less than 500 mg per day the antioxidant effect may predominate.

Clearly further studies are needed, in the meantime it would be wise not to exceed 500 mg vitamin C per day.

The key reference is by:

Podmore ID, Griffiths HR, Herbert KE, Mistry N, Mistry P, Lunec J

Division of Chemical Pathology, CMHT, University of Leicester, LE1 9HN, UK

idp@le.ac.uk

Vitamin C exhibits pro-oxidant properties

Nature 1998 Apr 9;392(6676):559

There is unfortunately no abstract